The present invention relates generally to method and composition for the treatment of acne and, more particularly, to such method and composition where the composition includes a diacyl peroxide of a medium chain fatty acid.
The dermatological term acne broadly denotes a number of different types of disease, the most common of which is Acne vulgaris which classically occurs before or during puberty. Acne vulgaris, which normally shows itself to be an illness of the sebaceous gland follicle, is constitutional in that it is caused and/or determined by endocrinological, bacteriological and biochemical factors. Androgens and certain estrogens stimulate the growth and function of the sebaceous gland. Shifts in the balance of these sex hormones in either favor and/or increased sensitivity of the sebaceous gland cells due to the influence of the hormones result in excessive sebum production and hypertrophy of the follicle opening. Comedones or "black-heads" consisting of sebum, cell and keratin masses are then formed which block the follicle opening and prevent discharge of the sebum. Sebum lipids penetrate through the fine ruptures of the enlarged follicle wall into the tissue causing lymphatic infection combined with the formation of pustules. This infection is typically caused by the grouping of the free fatty acids of the skin sebum.
Free fatty acids are not primary parts of the sebum but, rather, are formed secondarily during hydrolytic decomposition of triglycerides. The catalyst enzyme is a lipase of bacterial origin formed primarily by the anaerobic, gram positive, propionibacterium acnes which are part of the skin's bacterological flora. Thus, the comedones or "black-heads" contain a large number of the propionibacterium acnes and free fatty acids.
Acne is first observed clinically by the presence of closed and open comedones. When infection develops, Acne papulo-pustulosa, with its partially abscessed growths, and serious Acnes conglobata with its numerous fused growths develop.
Topical treatment of acne has three objectives:
the removal of the follicle hyperkeratoses and decomposition of the comedones to achieve a keratolytic and a komedolytic effect;
reduction of the acne using antibacterial agents; and
retardation of the lipase effect and a reduction of free fatty acids sebostatically.
The conventionally known preparations for the topical treatment of Acne vulgaris, some of which contain benzoyl peroxide, have not, to date, achieved these stated objectives. Benzoyl peroxide is a strong oxidizing agent which releases oxygen upon penetration into the follicle and thus creates aerobic conditions in the follicle which retards growth of the anaerobic bacteria. However, during decomposition of the dibenzoyl peroxide simultaneous with the release of oxygen, benzoic acid, a very skin-irritating material, is formed. Therefore, it is evident that the heretofore conventional compositions for the treatment of acne which contain peroxides exhibit considerable side effects, being particularly irritating when applied to the skin. Consequently, in about 10% of the cases, a contact-allergic sensitization occurs due to the topical application of dibenzoyl peroxide.
A primary object of the present invention is to provide a composition which is highly effective in the treatment of different acne forms and which has, even during a longer application period, no deleterious side effects.